Because of fiberglass's light weight and durability, it is often used in protective equipment, such as helmets. Many sports use fiberglass protective gear, such as modern goaltender masks and newer baseball catcher's masks. Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favorable when compared to metals, and it can be easily formed using molding processes.
One-two and three-dimensional space charge distributions in glass fiber/epoxy resin composites. By the conventional pulsed electroacoustic (PEA) method, only a one-dimensional distribution of the average charge over a whole area parallel to the two electrodes can be observed. Therefore, the authors have developed a new PEA system capable of measuring a three-dimensional space charge distribution. Using this system, they measured the charge distribution in glass fiber/epoxy resin composites made of lattice-woven glass fiber and epoxy resin. It has become clear that spatial variation in signal intensity observed depends on the internal structure of the composite. There appear repetitious positions where a high charge density is observed on the same lateral cross section along the vertical direction in the composite. Such positions are consistent with the intersections of the glass fibers. Accumulation of mobile charge carriers or appearance of polarization charge due to mismatch of the ratio of the conductivity and permit activity between the glass fiber and the epoxy resin is thought to be responsible for the PEA signals.
Unfortunately, there is the possibility of serious physical injury in sports such as football. Particularly serious are neck injuries which could be prevented by the present invention. The invention limits the movement in any direction of the head and neck during impact and thus prevents serious injuries. Abrupt and extended movements of the head are the cause of many injuries.